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Joshua Haynes
Joshua Haynes,
Category: Mercedes
Satisfied Customers: 273
Experience:  Lead Technician/ Manager at Precision Tune Auto Care
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Coolant ran out and heat light came on. All fixed, holding

Customer Question

Coolant ran out and heat light came on. All fixed, holding coolant, however it will run perfectly for a little while and then stall and stall and stall again and run really rough. Any ideas?
Submitted: 6 months ago.
Category: Mercedes
Expert:  Joshua Haynes replied 6 months ago.

Hi, my name is ***** ***** I will assist you.

Customer: replied 6 months ago.
Hi Josh, any ideas?
Expert:  Joshua Haynes replied 6 months ago.

It seems to me that you may have overheated the engine to the point of a combustion leak (blown head gasket). There is a simple test for this that involves a tool called a block tester. You can pick this tool up at the parts store for around $25 or ask a local shop to do it for you. The test involves warming the vehicle to operating temperature and then holding this tester over the coolant reservoir while it is open. The tester is filled with blue fluid that will turn yellow in the presence of combustion gasses (head gasket leak). If this test turns out positive, then you have a combustion leak. I hope this info helps!

Customer: replied 6 months ago.
It will run fine for a small amount of time. If the head gasket was blown, wouldn't it not run well at all?
Expert:  Joshua Haynes replied 6 months ago.

Yes, it is possible for the vehicle to run well for a short period of time, even with a combustion leak. But, nothing is a replacement for an actual test.

Expert:  Joshua Haynes replied 6 months ago.

Hi, this is Josh checking in to see if you have performed the combustion leak test yet?

Expert:  Joshua Haynes replied 6 months ago.

I also wanted to remind you to please take a moment and rate my service. Thanks!